In the Soft Boulder Cafe, each table has 3 legs, each chair has 4 legs and all the customers and the three members of staff have two legs each. There are four chairs at each table.

At a certain time, three-quarters of the chairs are occupied by customers and there are 206 legs altogether in the cafe.

How many chairs does the cafe have?



If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.